CROSS REFERENCE TO RELATED APPLICATIONS
Reference is made to the following commonly assigned copending applications:
1. U.S. Ser. No. 122,995, now U.S. Pat. No. 4,809,064, entitled ENLARGING PHOTOGRAPHIC PRINTER, filed Nov. 19, 1987 in the names of Shaun M. Amos, Richard J. Backus and Thomas C. Jessop.
2. U.S. Ser. No. 122,996, now U.S. Pat. No. 4,821,073, entitled METHOD AND APPARATUS FOR MEASURING CHARACTERISTICS OF PHOTOGRAPHIC NEGATIVES, filed Nov. 19, 1987, in the names of Patrick A. Cosgrove and Richard J. Backus.
3. U.S. Ser. No. 292,687, entitled LENS ADJUSTMENT APPARATUS, filed concurrently herewith in the name of Thomas C. Jessop.
1. Field of the Invention
This invention relates to alignment apparatus and more specifically to apparatus and a method for aligning a lens assembly with the optical center of an image sensing device in a video camera.
2. Description of the Prior Art
In apparatus of the type disclosed in commonly assigned copending applications Ser. Nos. 122,955 and 122,996 for producing prints of selected portions of negatives two independent optical systems are utilized. One system images the selected portion of the negative on the print paper and the other images the selected portion of the negative on an image sensor to display it on a television screen for customer observation. The customer has control of the negative and can, with the aid of the television system, create and crop the picture he wants. To produce accurate prints corresponding to what the customer sees on the television screen, it is fundamental that the television and printing systems agree for pointing and content.
In apparatus of the type described, accurate alignment of the camera to the zoom lens is required. The point on the sensor that corresponds to the center of the composing frame on the video screen must be on the axis of the zoom lens. This is referred to as the optical center of the sensor. If the optical center of the sensor and the axis of the lens are not coincidental, the image formed at the optical center of the sensor will be a field image for the lens. When the lens is zoomed, the field image will move due to the magnification change and cause a pointing error between the print and video systems.
One method of aligning the zoom lens is to clamp the lens and move a single point target to the zoom lens axis by adjusting the target relative to the lens. When the target appears stationary through a zoom, the camera can be moved relative to the clamped lens and target system to bring the sensor center into alignment with the non-moving target. This procedure is very inconvenient and time-consuming since the lens is supported by the camera.